#ASEslowchat Tuesday: Practicals

I can’t comment on what is happening in my classroom, or my department. Because I don’t have a classroom; instead I work with teachers in their classrooms, supporting their departments. So most of what I’ll be sharing will be at one step removed, but it is based on what ‘real’ teachers have told me is happening in their schools. I’ve played around with the stimulus questions a little.
Which required practicals have you completed with your classes; have you only completed these, or gone beyond them? Why?

I posted a little while back about how I felt the required practicals should fit into a balanced science curriculum. (This was a different post to one from even earlier, based o a draft of the AQA required pracs.) Nothing I’ve seen has caused me to change my mind. The summary is that whether a practical is required or not it should be used in the same way; to support teaching of science content and skills. It might, of course, be worth returning to the required practicals as part of the organised review/revision schedule, because they’re effectively content. Until then, ask the same questions, practise the same skills, as you would for any practical. (And, of course, don’t neglect these aspects if a practical is ‘unrequired’!)

Has the GCSE impacted on the work of the technicians in the department? Have you had any issues with equipment?

Not being in a school full-time, I’m not sure about the workload side of this. I don’t think it’s been a huge issue – certainly compared to lots of ISAs to worry about! (I hope school technicians are being encouraged to contribute to this topic, by the way.) But I have been doing a fair bit about the physics practicals with teachers, in school and by email, so I have a few resources to point to.

There is a dedicated TalkPhysics group for the GCSE required practicals – obviously just the physics ones. It’s fairly quiet at the moment, but I/we would love to see more teachers on there swapping ideas and answers, for example about specific components for I/V graphs or precise methods for using a ripple tank. If you’re not already a member, you can get a free login in a day or so, and the group is open to all. Technicians and all teachers of physics – not just physics specialists – are welcome. Please join in.

Most equipment issues I’ve heard about have been predictable:

• Getting a class around a ripple tank is hard. Much of the work can be done in pairs by putting a piece of laminated squared paper in a Gratnells tray – other trays are available – adding a centimetre of water with a couple of drops of ink, then making and timing ripples. Very fast, very cheap, and lots of data to criticise.
• Dataloggers for a=F/m. As you might expect, manufacturers are trying to log complete systems which will work brilliantly for a week then be a pain to set-up and calibrate. If you can use phones in school, kids can probably use slow-motion cameras to collect some useful data. Alternatively, I’m a huge fan (no commision, sadly) of the Bee Spi V lightgate. It displays either speed or acceleration of an object passing through it. It doesn’t log it, which to my mind is an advantage as it means kids have to do the table/points/line bit themselves. They’re £20 each, run on batteries and don’t need to be plugged into any device.
• The specific heat capacity practical – assuming you have the kit – has always produced data with, shall we say, lots to comment on. An improved method is available from PracticalPhysics, and it’s easier if you can (a) use a joulemeter and (b)record the maximum temperature, not the temperature at the end of the heating time.

How are you developing knowledge of practical work and investigations in your teaching ready for the examinations? 

‘Required Practicals’ is one of the sessions I run in schools as part of my day job with the IOP. So allow me to invite you to a virtual session, which will require you to imagine all the hands-on sections. There are presenter notes with even more links than in the slides themselves. PNCs will often run their own versions of these, and we do a lot at days and events open to all teachers. Please consider this an invitation.

If in doubt, checking out the work of Ian Abrahams is always worthwhile. He’s got a book out with Michael Reiss fairly recently: Enhancing Learning with Effective Practical Science 11-16, which I will buy as soon as my next freelance cheque arrives. Unless anyone would like me to review it, hint hint. He writes regularly in SSR so you’ve probably experienced a flavour of his work already.

A few years ago, Demo: The Movie was unleashed on an unsuspecting world by @alomshaha and co. It should be required watching for all science teachers and departments, and provides some great ideas about how to make demonstrations much better for learning. He’s got loads of films, some of which aren’t directly relevant but the techniques discussed are great. I reflected on some of the material in a blog post too.

Other resources I’d recommend (there will undoubtedly be some overlap) are collated at STEM Learning (the eLibrary that was, once upon a time). And I always like to put in a word for the SchoolPhysics materials by Keith Gibb, author of the Resourceful Physics Teacher.

Something I’ve chatted about in workshops, on Twitter and elsewhere; you may find it useful to break down the POE approach in a slightly more specific way which I call PRODMEE:

• Predict: what do you think will happen? (encourage specific changes to specific variables)
• Reason: why do you think that? (from other science content, other subjects, life experience)
• Observe: what actually happens? (we may need to ensure they’re looking the right way)
• Describe: in words, what happened? (qualitative results)
• Measure: in numbers, what happened? (quantitative results, devices, accuracy/precision, units)
• Explain: what’s the pattern and does it match the prediction? (digging into the mechanism)
• Extend: why does this matter? (other contexts, consequences for everyday life)

What resources or advice can you share with other teachers about approaching a specific required practical? What issues and opportunities have you come across when going about teaching the required practicals to your classes?

A few suggestions I’ve made in workshops, often based on conversations with teachers; this is obviously an incomplete list!

• Density is boring; why not provide a few blobs of blue-tac and have kids plot mass against volume on a graph. Make it more challenging by hiding a ball bearing inside one to provide an anomaly to the line of best-fit. Or can students separate LEGO, Mega-Bloks etc based on density?
• Hooke’s Law: as the kids have already seen it, why not try using strawberry laces? Alternatively, there’s a simple set-up using copper wire from PracticalPhysics. And you can always use it to hammer home the idea of science-specific vocab, because ‘elastic’ bands aren’t elastic.
• Acceleration: I mentioned Bee Spi V for measuring earlier. My only other suggestion is to always teach it as F/m=a so you start with the cause (force), shared out because of the conditions (mass) which leads to a consequence (acceleration).
• Ripples: discussed above, but you can also use a speaker as a vibration generator for some interesting results.
• Heat capacity: An old experiment uses lead shot which falls a known distance and heats up. Like stroking a metal lump with a hammer, this is a nice example of the idea that the energy in a thermal store can increase without ‘heating’ as we might normally consider it.
• I/V characteristics are a lot more interesting if students must compare results from a mystery component to standard graphs. This is included in the presentation of my workshop, linked above.
• Resistance, series and parallel: instead of just reusing the old ISA hardware, why not try taking measurements of different versions of squishy circuits dough?

 

 

 

 

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Energy Language Thoughts Part 4

Parts 1 (Introduction), 2 (Pathways/Processes) and 3 (Stores) are all available and will help make this more useful. Please continue to comment, on whichever post seems most relevant, if you’ve any queries or suggestions. Thanks to those who have already done so.

Practical Approaches

The IOP guidance begins by taking snapshots before and after an event and describing the changes to various possible associated stores. The alternative is to think about the physical processes – which will be variably familiar to students, depending on age – and thinking about the effect they have on parts of the system. YMMV.

The famous energy circus can be used, but be cautious! Some make much clearer examples than others. In most cases you will need to be very specific about the start and end points you wish the students to consider. I recommend checking out the SPT guidance. In particular, the ‘one step at a time’ diagram shows why chains of energy can cause problems. The suggestion there, which I endorse, is that you:

1. start with the idea of fuels ie chemical stores
2. make clear that fuels limit effects, they don’t by themselves cause the effects
3. give high, hot and stretched objects as equivalents, but as they’re clearly not fuels we associate them with
4. gravitational, thermal and elastic stores respectively

Explained at SPT

I’d suggest looking at your energy circus for clear demonstrations of these to begin with. Next would come a kinetic store, probably as an endpoint. A gyroscope or Newton’s cradle is a nice example of a kinetic store which lasts long enough to be plausible.

Approaches to consider

You could have a first round to develop some basic ideas, then a second with more complex snapshots (either more than one store involved at the end, or the same kind of store but associated with different objects).

Have students identify just the stores to begin with, discuss them as a class, then come back and add descriptions for the processes. This could be split between lessons; that way you can provide correct stores in the second lesson and concentrate on processes. In some cases, such as the classic filament bulb, two similar pathways will be needed.

• From: thermal store of filament
• Via: heating by visible radiation, heating by IR radiation
• To: thermal store of air in the room

If you want them, here are energy-circus-cards as pdf (includes example and blank cards)

Provide sets of laminated cards with stores, and arrows for the descriptions of processes. Labelled arrows are of course an option, but be aware of limitations and I’d include some blanks.

Again, cards-for-energy-v3 as pdf to save you a few minutes.

An extension could be to suggest measuring equipment and/or units for the relevant stores in each situation. If returning to these examples at GCSE, then recall of the equations are the natural next step.

Consider including actual photographs for some situations that cannot be easily reproduced in the lab; this would be a good way to introduce some examples from biology and chemistry. A food chain in biology might, for example, be described so:

• From: chemical store of lettuce
• To: chemical store of rabbit

Then

• From: chemical store of rabbit
• To: thermal store of rabbit, kinetic store of rabbit, chemical store of fox

And finally

• From: thermal store of rabbit, kinetic store of rabbit
• To: thermal store of air

For chemistry, exothermic reactions will involve heating by particles and/or heating by radiation pathways. If the material explodes (which in my experience is the preferred result) then there is some kind of mechanical working too, yes? Be prepared for questions about state changes; the best approach is that latent heat means the thermal store is not only identified by the temperature change. Which, yes, is a complication.

It’s probably worth adding notes – mental or otherwise – to the other science topics so you can remind students of the new language. If you have particular queries, drop me a line in the comments or, for a more considered answer, join in with the discussions on TalkPhysics.

This seems like a good chance to consider the Big Ideas in Science Education. Which should be up anyway, somewhere, but it’s always nice to have a reminder.

Exams and Textbooks

This is where I must admit defeat. I know – in fact I started the first post in this series with this point – that teachers want to know what will get marks and what won’t when it comes to the exams. Sadly, I don’t know. At least one board used the old language in the sample papers originally made available. The list of stores is not consistent between boards, though I hope that makes more sense after Part 3. And so on.

I’m sure we’ll all be happier once we see more examples of possible questions, but I’m not involved much with the boards so I have no insight. My advice – which isn’t official IOP guidance, nor is it specially informed – is that if your students can explain the mechanisms behind the transfers, they shouldn’t need to worry about the language, either pathways or processes. For the stores, it’s probably more important that they can identify the equations that are relevant and be able to do the maths – that, of course, hasn’t changed! I’ve recently discovered that Richard Boohan is putting together some materials; I shall be watching with interest.

Whether students will be penalised for talking about light energy, sound energy, electrical energy – that I don’t know. I also don’t know how much emphasis will be placed on this language by those marking biology and chemistry questions. So I’m not much good, really. Sorry!

Last appeal for comments, feedback, criticism… please let me know what you think of these four pieces. At well over 3000 words I appear to have accidentally written an essay. I hope that if you’ve waded through it, you feel it was worth your time. Please do give me a shout if there’s something I can do to improve the time spent vs time saved ratio.

Required Practicals

Morning all. I was at the Northern #ASEConf at the weekend, had a good time and had lots to think about. I’m going to try really hard to blog it this week, but I’m buried under a ton of stuff and pretty much every person in my immediate family is either ill, recovering or about to go into hospital. And Trump apparently won, which makes me think it’s time to dig a fallout shelter and start teaching my kids how to trap rabbits for food.

Anyway.

One of the recurring discussions between science teachers is about the new required practicals for the GCSE specs. I’m trying to put some resources together for the physics ones as part of my day job, on TalkPhysics (free to join, please get involved) and thought I’d share a few ideas here too.

Who Cares?

The exam boards don’t need lab books. There is no requirement for moderation or scrutiny. There is no set or preferred format. And, realistically, until we’ve seen something better than the specimen papers there’s no point trying to second-guess what the students will be expected to do in the summer of 2018.

So apart from doing the practicals, as part of our normal teaching, in the normal way, why should we do anything different? Why should we worry the kids about them? Why should we worry about them? There’s time for that in the lead up to the exams, in a year’s time, when we’d revise major points anyway. For now, let’s just focus on good, useful practical work. I’ve blogged about this before, and most of it comes down to more thinking, less doing.

Magic Words

What we can do is make sure kids are familiar with the language – but this shouldn’t be just about the required practicals. So I put together some generic questions, vaguely inspired by old ISAs (and checking my recall with the AQA Science Vocab reference) and ready to print. My thinking is that each laminated card is handed to a different group while they work. They talk about it while doing the practical, write their answers on it, then they get added to a wall in the lab. This offers a quick review and a chance for teachers to see how ids are getting on with the vocab. The important thing – in my view, at least – is that it has to be for every practical. This is about improving fluency by use of frequent testing. And it ticks the literacy box too.

EDITED: more cards added, thanks to suggestion from @tonicha128 on Twitter.

So here you go: prac-q-cards-v2 as PDF.

Please let me know what you think, whether I’ve made any mistakes, and how it works if you want to try it out. It would be easy to produce a mini-test with a selection of these questions, or better ones, for kids to do after each practical. Let’s get them to the stage of being so good with these words that they’re bored by being asked the questions.

GCSE Practicals

You’ll already know that the assessment of practical work is changing. (I recommend this article by Alistair Moore and this at the RSC from @MaryUYSEG for useful perspectives.) At A-level it’s changed already, as part of many other alterations. The ISAs are gone for post-16, and it’s fair to say that most teachers aren’t going to miss them. At GCSE these changes will be part of the new specification which officially starts in September 2016, and which many schools have already started to use for their Year 9 students. Which is brave, when they’ve not been approved yet! If you’re teaching A-level Physics I’d recommend the resource created by one of my day-job colleagues at the SPN and available to all.

Different exam boards are taking different approaches, but there’s a big overlap. Each has a list of practicals which are required/recommended/suggested, and students will need to have a signed form of some kind which says they’ve done them. This means they’ll have had the opportunity to gain all the relevant skills (according to OfQual) which will be a pass/fail ‘extra’ to the grade. I predict, somewhat cynically, that the vast majority of students will have gained these skills on paper no matter how much their lab work resembles that of Beaker from the Muppets. 15% of the final exam marks will be awarded for students demonstrating in a written exam that they can think like a scientist, probably in a similar way to the ISA papers.

The list of practicals is a minimum expectation – a lower limit rather than an upper one. Most are ones we have always done, in one form or another. Students don’t have to work independently on all of them, or in exam conditions. They need not (and in my opinion should not) do them as a separate unit or topic but as part of their normal experience of science, alongside science content and social context. There is no specific way they are expected to write them up or record their results.

My plan is to create a resource list for each of the GCSE Physics practicals, drawn from AQA, Edexcel and OCR. These are my interpretation and, certainly at the moment, I’m doing them in my own time for no charge. (If anyone would like them sooner and/or to sell, contact me with a price in mind.)

Science Club: Building with Pasta

Quick and easy practical, instant gratification, cheap materials (that you can eat at the end). Yes, the first in our series of science club activities was always going to be Spaghetti Towers.

Materials

• spaghetti (1 pack per four kids)
• marshmallows (1 pack per four kids, no eating until the end)

Play, Look, Ask (from the Ri site)

• Make a tower from spaghetti and marshmallows.
• ExpeRiment with the construction of your tower to find out which shapes are best for building with.
• Learn why some shapes are more stable than others when you build a tower.

I had a vague idea of how things would go. Some of it was right; a lot of it wasn’t. The kids had a great time and, I think, learnt a little bit too. We started by talking about buildings, then I challenged them to make shapes with the marshmallows and pasta. Several of the kids – aged 5 or 6 – enjoyed this so much it was hard to get them to move on. The next step was to try making something to stand up. Before too long we were able to lead them to the idea that squares fell over. A couple of better examples showed that triangles worked well, and soon there were many weird and wonderful structures taking shape.

About twenty minutes from the end I asked them to pause and showed a few pictures on the IWB of buildings. The kids were very excited to point out the triangles on the Eiffel Tower and the Forth Bridge. They were not, however, able to translate these to very regular shapes in their own building. There was a lot of discussion about whether we should test the buildings by pushing from the side or above – an interesting approach would be to add a fan to simulate wind. Perhaps with older students! Most of them were happy to explain that the buildings needed a strong shape as well as a strong material, which I was pleased with.

Next time – because we’ll be repeating the cycle each half-term with another group of pupils – I’ll aim for a clearer structure from the beginning. It was harder to get them back on track than I expected. I’m used to being able to ‘steer’ consensus in secondary, but the kids listened, nodded, then carried on doing exactly what they were doing before I’d spoken.

Next time

1. Picture of a building (if the IWB is working and the blinds are drawn).
2. Start with flat shapes (set time limit)
3. What will happen when we stand them up?
4. Try it out, then ask what the best shape is and how we know (time limit).
5. What shapes are strong? (triangles are good, squares and more sides can be deformed.)
6. What makes a tower ‘the best’? (tall, withstands load, withstands force from side?)
7. Allow time to build the ‘best’ tower

Things to track more carefully:

• different views of ‘scientist’ and engineer’
• words used eg strong, bendy

 

 

Science Club: Shortlist

My son’s primary school was looking for more after-school activities. My wife was at the meeting where they discussed the possibilities. And I’m a science teacher with a bit of spare time as my current role is both part-time and out of the classroom.

You can see where this is going, can’t you?

The shortlist

I quite liked the idea of working with kids directly, but I was very aware that as a secondary teacher I needed help. Besides, reinventing the wheel lacked appeal. I had a look at various ‘bought-in’ structures, for example some of those presenting at the ASE Conference. But they were quite expensive. I checked out ideas through STEMnet, many of which were aimed more at KS3. In the end, I presented the science coordinator with two options I felt would provide interest without a huge workload.

The first, predictably, was via the British Science Association: specifically the CREST Star awards for ages 5-11. (I have fond memories of BAYS from my own school days.) There’s a library of activities and kids gain the award after completing a certain number of them. Depending on the age and ability you choose different themed sessions, all of which have support materials ready to use.

The other was slightly less formal. I was fascinated by the ExpeRimental project from the Royal Institution last year, and blogged about it. The idea of providing materials for parents to have scientific fun with offspring is a great one. The second series of videos looks as enjoyable as the first. And I happen to know one of the people behind it, my good friend and virtual colleague @alomshaha. So it seems a natural step to suggest it for a science club for ages 5-6.

The choice

We’re going with ExpeRimental; partly because it’s free, and partly because it means we can provide easy links for interested parents. But mostly because it looks great fun. I’ll be blogging each week about how it went, good and bad, and sharing a few photos of the results (but not the kids). Hopefully a longer piece about the experience will make it to the RI website once we’ve finished the first half-term cycle. I really feel that many of the activities would work well with older students, too. In fact, I’d argue that some of them would provide a challenge for sixth form students if you simply changed the questions you asked. And isn’t that a great recommendation for practicals built from kitchen cupboard and junk box materials?

Skills Lists

I’m going to keep this brief in the hope it actually gets (a) finished and (b) published. Because I’ve several drafts that I’ve just not found the time or motivation to finish off. In context; I have a small child, a shortage of caffeine and a grumpy temperament. This may be because not one new blogger built on my #aseconf session and contributed a post. Humph.

Recently, the skills vs knowledge debate has kicked off again. Not that it ever really went away! I think like many teachers, I actually stay away from both extremes. Of course kids need to know (ie recall with fluency) some facts. The question is where you draw the line. Do I expect my GCSE students to remember that Carbon has a proton number of 6? Of course I do. Do I expect them to memorize the entire periodic table, with or without the song? Of course I don’t. This could be applied to the reactivity series, the equations of motion, geological era or pretty much any other part of science. Knowing some is vital, knowing them all is unnecessary. But discussion online – perhaps especially on twitter – tends towards the argumentative.

So arguments about what should and shouldn’t be in the national curriculum, exam specifications or whatever are doomed to end unresolved. And, let’s face it – as teachers we don’t often get a say in it. We just have to make the best of what we get.

Instead, I was kicking some ideas around with colleagues and ended up with the bastard offspring of APP for younger kids and logbooks as suggested for AS, via ‘loyalty cards’ which I blogged after stealing the idea from @ange01. Hold on, it makes sense. Kind of.

Why not, I reasoned, put together lists for the students to use to record their various competencies? (I did something like this for teacher standards, although I’ve stopped keeping track of it. When I get around to it I’ll create a version for RSci and CSciTeach recording categories and wave it at @theASE via twitter.) This fits in well with the new approach to practical work at post-16, something else which has divided teachers and politicians alike. I made several deliberate decisions for the sample below, but I was very much thinking this would be better put together collaboratively, exam-board agnostic and perhaps led by expert/subject associations. (It would be interesting to have input from universities too, although I’ve a post brewing about university involvement in curriculum design too…)

1. These are solely hands-on skills for the school lab – no analysis, no maths. There is no content. (Although it might be interesting to produce a paired list, with knowledge on the left and skills on the right. Hmm. Notes for later.)
2. I ignored exam specifications and instead flicked through the relevant pages on PracticalPhysics. I’ve probably missed something, suggestions welcome.
3. Instead of a ticklist, my idea was for students to add a date each time they demonstrated that skill. I suspect teachers would have varying ideas of how many times are needed. The only thing everyone will agree on is that once is not enough.
4. This is for students to use themselves for tracking, not teachers to use for assessment. I hope HoDs are paying attention to this point.

It would be easy to use this approach for GCSE and AS/A2, one checklist per topic area. (I’m sure many colleagues and departments already do.) But why not spend a little time putting together a good list, based on agreed best practice? I do similar things for content revision, but it’s the first time I’ve done it for specific hands-on skills. I’m going to have a play around with a ‘minds-on, thinking scientifically’ version too.

I’d happily run a project producing high quality versions, based on wider consultation, for all subject areas. It would need more of my time and the time of colleagues. That means money, so let me know if you know where I could submit a proposal for funding…

One I Made Earlier

I had an old webcam. I had time on my hands. And I had an idea.

This was never going to end well.

I’m actually pretty pleased with the result. It’s nowhere near as pretty as the one on Instructables produced by Glen Gilchrist (aka @mrgpg) but it didn’t need any power tools. Which were in the shed, and it was raining.

Start with an old webcam and a cheap lamp, in this case one from Ikea. It’s the sort of thing you might have, just make sure it has a long neck  which holds the head steady. It will need to support a bit of extra mass. (Not weight. Well, yes, weight. Anyway.)

 

I used Lego, Sugru and cable ties to hold everything together. This has the advantage of being reversible, as well as quick. How you link the two parts depends on the exact models, but Lego means angles can be fixed and changed to suit your purpose. Plus, you know, Lego.

Sugru feels like blue-tack but dries within 24 hours to a firm silicone rubber. I’ve used it for outdoors repairs, making cufflinks (again with Lego, as it happens) and repairing odds and ends from cables to memory sticks. They don’t sponsor me. (Although if they want to send me some free samples…)

It works fine on my laptop, but I’ll need to try installing the drivers on a memory stick to make it properly portable. The plan is to demonstrate this in my new job and try it out myself, without the cost (100UKP+) involved in the decent models. I’ve read about uses (for example these for primary science from @dannynic) but never had the chance to put them into practice.

My first thoughts:

• use student work immediately for “good because” and “even better if”
• turn a small-scale practical into a class demonstration
• have a student commentate on an experiment in progress
• show hands-on methods like measurements and graph drawing in a realistic way

Not particularly exciting, I know, but I’m expecting to do a lot of improvisation in the new job. I’m currently putting together boxes of demonstrations, quick practicals, tips and tricks for the teachers I’ll be working with. (Post about this coming soonish.) But for now I’d love to have comments giving me better suggestions for how to use my Blue Peter Sugrued visualizer.

Moving Beyond Predict/Observe/Explain

I don’t remember when I first used the idea of breaking down a demonstration for students by having them follow the POE format:

• Predict what will happen
• Observe what actually happens
• Explain it in context

I think a lot of science teachers used this before – or even without – referencing the ideas of Michael Bowen, who explains the approach in this video. He wasn’t the first, but I tracked down the link via the site of the National Science Teachers Association in the US. There are several papers available there, for example this from a decade ago about hypothesis-based learning, which makes explicit the difference between a hypothesis and a prediction. It’s easy to see how these steps link nicely with a 5/7Es planning method. But I think it’s worth adding some steps, and it’s interesting to see how it might have developed over time. How students cope with these stages is an easy way to approach formative assessment of their skills in thinking about practicals, rather than simply doing them.

Please note – I’m sure that I’m missing important references, names and details, but without academic access I simply can’t track original papers or authors. My apologies and please let me know what I’m missing in this summarised family tree!

PEOE: I think this because…

To stop students making wild speculations we need to involve them in a conversation justifying their predictions. I suppose this is a first step in teaching them about research, to reference their thoughts. I find this needs guidance as many students mix up the two uses of explain; the derivation of their prediction and the link to accepted theory.

PODME: Recording what we observe

I got this from Katy Bloom (at York SLC, aka @bloom_growhow) I think after chatting at a TweetUp. I’m paraphrasing her point: in Science it’s not enough simply to observe, we must also share that observation. This can take two forms, Describing in words and Measuring in numbers. The explanation then becomes about the pattern rather than a single fact or observation. Bonus points to students who correctly suggest the words qualitative and quantitative for the observations here!

PBODME: My current approach

I’ve tweaked this slightly by making the first explanation phase explicit. The display is on the wall and students can apply this (with varying degrees of success) from year 7 practicals with burning candles to year 13 physics investigations into gamma intensity affected by thickness of lead shielding.

• Prediction of outcome
• Because of hypothesis based on life experience, context or research
• Observation using senses, measuring devices
• Description in words of what typically happens (sometimes as commentary during practical)
• Measurement using appropriate units, with derived results and means where needed
• Explanation of results, patterns, anomalies and confidence

Is it getting ungainly? Having this structure means students can see the next step in what they are doing, and are hopefully able to ask themselves questions about how to develop a practical further. I suppose you could argue that the original POE approach is the foundation, and these stages allow us to extend students (or ideally allows them to extend themselves).

PBODMEC: Why does it matter?

In many ways, the natural next step would be about Context – why should we care about the results and what difference do they make to what we know, what we can do or what we can make?

I plan to follow up this post with the printable resources (wall display and a student capability checklist) but they’ll have to wait until I’m home. In the mean time, I’d welcome any thoughts or comments – especially any with links to other formats and their uses in the school science lab.

Demonstration or Class Practical?

It’s always a tricky one, isn’t it? Do we show them the experiment, knowing that a half-dozen or so will be messing around at the back or comparing nail varnish with their friends? Or do we let them loose with glassware and clamp stands, waiting for the crashing noises or the blank looks to begin?

Okay, I’m exaggerating. A bit. But for most of us, it’s probably taking a bit of time to think about the kinds of practicals we do, and why. Are we focused enough on what the students will learn from it? Or are we doing a particular practical or demonstration because it’s in the scheme of work, or because we’ve always done it?

I’ve used among other sources David Sang and Alom Shaha’s workshop at the ASE Conference and materials from Getting Practical and SCORE Education to produce a checklist (downloadable below, simply click on the image). The focus is about the benefits of a demonstration or a class practical. It’s an easy way to think about what can be added to an activity, or ways to tweak it to improve outcomes. Simply sharing with the students what they might be trying to gain from a practical is worthwhile – although in some cases as a plenary to avoid spoiling a surprise or insight. Simply take a moment to read through the lists, and see if you can justify the activity in terms of learning. If you’re not sure, what could you change?

There’s loads of good ideas online – the National Stem Centre eLibrary is of course one place to look – and it’s often possible to convert a practical into a demo or vice versa. For example, I demonstrate heat transfer in fluids using the two chimneys apparatus and a convection square, plus hot and cold water with food colouring in gas jars, which I first saw in ‘Nina and the Neurons’. By the third demo the kids can predict and ex0plain what’s going to happen quite well. I then give them coloured ice cubes to float in water, and to predict, explain, describe and explain again (PEOE) what they see. Bonus points for a commentary that uses key ideas such as ‘density change’.

I hope this kind of reminder is useful, for experienced teachers as well as those more recently joining the profession. Feedback would be very much appreciated, as this is my 100th post and I’ve had less than 1 comment for each on average…